[clang] [clang] Add support for SerenityOS (PR #187941)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-with-thin-lto-ubuntu` running on `as-worker-92` while building `clang` at step 7 "test-stage1-compiler".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/127/builds/6956

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 7 (test-stage1-compiler) failure: build (failure)
...
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld.lld: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/ld.lld
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/lld-link
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/ld64.lld
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/wasm-ld
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld.lld: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/ld.lld
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using lld-link: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/lld-link
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using ld64.lld: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/ld64.lld
llvm-lit: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/llvm/utils/lit/lit/llvm/config.py:569: note: using wasm-ld: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/wasm-ld
-- Testing: 93176 tests, 72 workers --
Testing:  0.. 10
FAIL: Clang :: Driver/serenity.cpp (14118 of 93176)
******************** TEST 'Clang :: Driver/serenity.cpp' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 4
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -### /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree    -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir    2>&1 | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATHS
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang '-###' /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATHS
# RUN: at line 8
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -### /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=aarch64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree    -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir    2>&1 | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATHS
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang '-###' /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=aarch64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATHS
# RUN: at line 12
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -### /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=riscv64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree    -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir    2>&1 | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATHS
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang '-###' /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=riscv64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATHS
# RUN: at line 23
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -### /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree    -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir    -fsyntax-only -nostdinc 2>&1 | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATH_NOSTDINC
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang '-###' /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir -fsyntax-only -nostdinc
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATH_NOSTDINC
# RUN: at line 30
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -### /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree    -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir    -fsyntax-only -nobuiltininc 2>&1 | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATH_NOBUILTIN
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang '-###' /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir -fsyntax-only -nobuiltininc
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATH_NOBUILTIN
# RUN: at line 41
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -### /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree    -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir    -fsyntax-only -nostdlibinc 2>&1 | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATH_NOSTDLIBINC
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang '-###' /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unknown-serenity --sysroot=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/serenity_tree -resource-dir=/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/Inputs/resource_dir -fsyntax-only -nostdlibinc
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=PATH_NOSTDLIBINC
# RUN: at line 52
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -c /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unkown-serenity -### 2>&1    | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=CHECK-PIE2
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -c /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=x86_64-unkown-serenity '-###'
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=CHECK-PIE2
# RUN: at line 54
/home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -c /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=aarch64-unkown-serenity -### 2>&1    | /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=CHECK-PIE2
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/clang -c /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --target=aarch64-unkown-serenity '-###'
# executed command: /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/build/stage1/bin/FileCheck /home/buildbot/as-worker-92/clang-with-thin-lto-ubuntu/llvm-project/clang/test/Driver/serenity.cpp --check-prefix=CHECK-PIE2
# RUN: at line 56

```

</details>

https://github.com/llvm/llvm-project/pull/187941